how to iterater map of sets in c++

To iterate over a map of sets in C++, you can use nested loops. Here is an example of how you can do this:

#include <iostream>
#include <map>
#include <set>

int main() {
    std::map<int, std::set<int>> myMap;
    myMap[1] = {10, 20, 30};
    myMap[2] = {40, 50};
    myMap[3] = {60};

    // Iterate over the map
    for (const auto& pair : myMap) {
        int key = pair.first;
        const std::set<int>& values = pair.second;

        // Iterate over the set
        for (const auto& value : values) {
            std::cout << "Key: " << key << ", Value: " << value << std::endl;
        }
    }

    return 0;
}

In this example, we have a map called myMap that maps integers to sets of integers. We populate the map with some values for demonstration purposes.

To iterate over the map, we use a range-based for loop with the syntax for (const auto& pair : myMap). This loop iterates over each key-value pair in the map.

Inside the loop, we extract the key and the set of values using int key = pair.first and const std::set<int>& values = pair.second.

To iterate over the set, we use another range-based for loop with the syntax for (const auto& value : values). This loop iterates over each value in the set.

Inside the inner loop, we can access both the key and the value. In this example, we simply print them out using std::cout.

The output of this code would be:

Key: 1, Value: 10
Key: 1, Value: 20
Key: 1, Value: 30
Key: 2, Value: 40
Key: 2, Value: 50
Key: 3, Value: 60

This demonstrates how to iterate over a map of sets in C++.